This invention relates to an engine output control and more particularly to an improved method and apparatus for controlling the output of an internal combustion engine to improve performance at partial loads.
A various number of types of arrangements are provided for controlling the output of an internal combustion engine. The term "output" is employed so as to indicate either the speed or torque which the engine develops. This can be done in a variety of fashions. For example, with spark ignited engines the output is controlled at least in part by a throttle valve that is positioned in the induction system of the engine. With a diesel engine, on the other hand, the output may be controlled by changing the timing and/or amount of fuel injection or fuel supplied to the engine.
In addition to these basic controls, other aspects of the engine which can also affect its output may be changed along with the basic output control. For example, with spark ignited engines the output may be also changed by changing the spark timing, fuel supply amount and timing, amount of exhaust gas recirculation and other factors. Generally these controls are operated by a linkage system from the operator controlled member and are done in some form of sequencing. However, the main control is moved between its closed or idle position and its wide open maximum output position in response to like movement of the operator controlled member. It has been found, however, that these systems can preclude the obtaining of optimum performance, particular at partial loads.
It is, therefore, a principal object of this invention to provide an improved engine output control.
It is a further object of this invention to provide an improved method and apparatus for controlling the output of an engine so as to improve performance at partial loads in the way of both fuel consumption and exhaust emission control.